The invention relates to lip and cheek expanders for use when performing dental medicine, dental hygiene or dental-documenting activities.
During the aforementioned activities it is usually necessary to keep the lips and cheeks that come into abutment with the rows of teeth away from the rows of teeth, in order to free up a sufficient working space, to make the necessary inspection conditions possible and to reduce the risk of damage to the lips and cheeks.
When performing activities in the side area of a row of teeth, the respective cheek is kept away or retracted by exerting a force on the lip or the cheek via a so-called cheek retractor, via the mouth mirror or via a retractor hook. These pressure loadings can lead to pressure marks or swellings on the lips and cheeks or cause pain.
Such retractors, which are usually made of metal, are suitable exclusively for freeing up one side of a working space. To perform activities in different areas of the rows of teeth, however, cheek retractors designed in various ways are necessary for the retraction to be effective. Not least, mouth mirror, cheek retractor and retractor hook must be guided by hand. As a result, either the dentist providing the treatment now only has one hand at his disposal, and/or an assistant is needed in addition to hold the retractor. The restricted working space requires a precisely coordinated interplay of the movements of the person performing the treatment and the assistant. Moreover, with such instruments even the most skilled assistant cannot succeed in keeping away or retracting the sensitive lips, corners of the mouth and cheeks to the complete satisfaction of the patient and of the person performing the treatment.
Metal spreader clamps which expand the mouth opening are known for carrying out activities in the front area of the rows of teeth. These clamps can be provided with metal lip shields for the more uniform introduction of the spreading forces.
Spreader clamps are also known in which pre-formed lip shields and a spreading apparatus rigidly connected to the latter are formed by a single plastic injection-molded part. Unlike the previously mentioned metal instruments they do permit a somewhat gentler retraction on the one hand, but on the other hand a sterilization is possible only to a limited extent, as plastics that can be used for this purpose are generally not autoclavable. However, if sterilization is insufficient, herpes labialis for example, which frequently occurs on the lips and corners of the mouth, is easily transmissible.
Also, it is not possible with conventional instruments—because of their design—to keep the lips and cheeks away from the rows of teeth over their whole length at the same time. Moreover, patients find the alternate pushing and pulling with such instruments unpleasant.
Keeping away or retracting the lips and cheeks in question by means of conventional instruments on the one hand restricts access to the oral cavity and can on the other hand—in particular if fitted for a prolonged period—lead to traumatic postoperative phenomena in the area of the lips and cheeks.
Thus, a protective body with a pre-formed U-shaped longitudinal profile, which is made from a soft, elastic material, is known from DE 83 23 817 U1. If one of the lips is inserted into this U-shaped protective body, it is actively protected by the protective body against injuries caused by the treatment tools. This protection can be further increased by additionally incorporating into the U-shaped protective body reinforcements made of special steel wire. One embodiment of the invention ensures that the mouth opening is kept open, but not that the lips are kept away from the rows of teeth. For such a retraction in the front area, a further embodiment is disclosed which is characterized by a metal spacer bracket additionally attached to the protective body. This spacer bracket, which can be supported against the row of teeth lying behind the protected lip, ensures the desired distance between the lip and the row of teeth. However, painful pressure marks are usually caused by this type of support.